The invention relates to communicating direction information between two or more entities.
The ability to communicate efficiently and effectively is critical in many professions, especially when a dangerous mission-critical operation involves the cooperation and coordination of a group of individuals. Police officers, firefighters, rescue divers, soldiers, etc. all recognize the importance of teamwork, and routinely rely on good team communication to survive and accomplish their tasks.
One type of message commonly used in intra-team communication is a message that includes a “directional reference”, i.e. an indication of an explicit or implied direction relative to some frame of reference. The following are all examples of statements that have at least one directional reference (explicit references are underlined):
1. “Evacuate in this direction!”
2. “Hostile approaching from that direction”
3. “Look!”
4. “Targets located there, there and here.”
5. “Spray those beams with water.”
6. “Incoming, two  o'clock”
A “directional reference” is an action that is intended to indicate a direction. The “direction information” describes the direction indicated. Direction information is expressed in relation to a coordinate system (“frame of reference”).
In practice, directional referencing can be done verbally and/or visually. Directional referencing is often done with visual signals or cues—usually some sort of gesture to indicate/confirm the intended direction (“this way”, etc.). For example, a soldier may verbalize that an enemy is approaching and simultaneously wave towards the direction of approach. Other examples include: a hunting dog that identifies the location of game by assuming a characteristic posture towards the direction of the game; a police officer that commands movement in a particular direction by nodding their head; and an air traffic controller that guides taxiing aircraft by waving a lighted wand in a certain direction.
Visual signals are intuitive for an individual to perform, and are also easily understood by individuals observing them. These individuals may already convert the indicated direction subconsciously into a direction relative to their own frame of reference.
However, visual signals are ineffective when direct visual contact is impossible or interrupted between the signal originator and the intended recipient(s). Urban and dense environments limit visibility and field of vision, and provide challenges for team communication. Additionally, smoke or darkness may obscure and interfere with the visibility of visual signals.
Verbal messages (talking/yelling, perhaps over a radio) achieve near-instant information transfer, often without the need for direct visual contact between the communicating parties. However, verbal directional referencing requires additional information to be supplied so that the targeted recipients of the message can understand the intended direction without relying on the visual cue.
This additional information is usually in the form of a “frame of reference”, and there are three possible frames of reference: (1) the originator's frame of reference, (2) a receiver's frame of reference, and (3) an absolute frame of reference as shown in FIG. 1. With phrases like “To My Front!”, “[Get] behind me!”, or “Exit to my right!”, the originator is conveying direction information with respect to their own frame of reference. The recipient of this message must be aware of the originator's orientation/position (or the originator's orientation relative to the receiver's orientation) to know understand the direction information.
Messages like “To Your Left!”, “Watch your step!”, or “Exit to your right!” are based on the receiver's frame of reference. While easy for the receiver to process, these require the speaker to be aware of the receiver's orientation/position. Furthermore, the presence of multiple receivers facing different orientations will complicate the process.
Messages like “[Proceed] Southwest” or “Head towards the flagpole” contain an absolute reference and require both parties to be aware of the their orientation or surroundings. For absolute cardinal directions, the originator has to first determine the appropriate direction to convey (e.g. by consulting a compass), and the receivers must understand how this direction affects them (e.g. by consulting their compass) and how to react to it (e.g. by understanding their orientation relative to the indicated direction). This manual double-translation process is undesirable and inefficient in certain situations. In addition, this process may be subject to interpretive error, particularly in mission-critical time-pressing situations.
Instead of using cardinal directions, a common front can also be established. In low intensity situations, a team can issue statements relative to this common front, e.g. “cover left rear!” or “enemy, front right!”. However, in dynamic situations, the team front is constantly and rapidly changing; it is risky to assume that all team members, who are moving around and oriented differently, are completely conscious of what is currently defined as the team's front.